Rear.
Image Dynamics CTX-69 6x9's (100 RMS @ 4 ohms each) and power them with an old school Alpine 3523 I have lying around puts out ~40 RMS x 2 @ 4 ohms (from the 80s some people say it puts out more, I don"t know)

I might add a sub later, I just wanna upgrade speakers now and get the best sound without buying any more amps.

Would I be okay powering this setup like this with proper gains? Would I have too much front stage? I don't like the idea of completely ditching rear speakers which is what I found a lot of people suggesting. My car is huge and I don't think front speakers alone will fill the cabin with sound.